I also found myself wondering how an Empire of a Million Worlds formed before Melange gave the Spacing Guild the ability to shuttle everyone around. Is this explained in the Butlerian Jihad book? I understand the Holtzman engine is what folds space and the Navigators merely find a safe path, but I fail to see how the Holtzman is useful without prescience. Without foldspace AND Navigators, interstellar travel and the forming of this HUGE empire would be next to impossible (especially in a mere 10,000 years). See below.
Light moves at a velocity of about 300,000 kilometers each second. So in one year, it can travel about 9,500,000,000,000 km. The distance to the Andromeda Galaxy, is 21,000,000,000,000,000,000 km.
